Used Android Studio to make it so it should be standard procedure for editing it. I'm also new to this so forgive my noob-ness.
Head over to the release if you are actually interested in this app I made for a senior project in high school.
Development of Playtime Calc is probably not going to continue, but if anyone got some kind of use out of it, that would be fine by me. If you are interested in my work, please check out my Github profile for newer projects that I am actually planning on continuing.